The present invention relates to an anti-friction bearing unit for machines processing synthetic resins, having an outer and an inner running or race surface and rolling bodies placed between the race surfaces and spaced from each other by a ring-like cage.
With certain machines for processing resins there are very stringent demands with respect to bearings, this being more specially true of, for example, machines for processing waste resin under very high pressures and temperatures to produce regenerated resin. An account of such a machine is given in the German Pat. No. 2,700,846, in which comminuted resin or plastic scrap is plastified by squeezing between the rollers or a press, which produce the high pressure needed not only for plastifying but also for expelling the plastified regenerate from the machine. Because of the high radial pressures and the relatively high temperatures, it is not possible for plan bearings to be used for the squeezing rolls. Furthermore however conventional anti-friction bearings are not suitable either. Because of the high temperatures normal lubrication fails and there is also a strong chance when processing scrap resin of foreign bodies, as for example nails, being present in the resin and being swept along with it into the bearings. Lastly, the cages of conventional anti-friction bearings would not be able to stand up to the high pressures involved.